Relationship of nutrients and food to colorectal cancer risk in Koreans

To elucidate possible associations between dietary factors and colorectal cancer in the context of the Korean diet, a case-control study was conducted in Seoul, Korea. Cases (n = 136) were patients either newly diagnosed with colorectal cancer or with large bowl adenomatous polyps. Control patients (n = 134) included those with no history of cancer and conditions potentially unrelated to nutritional status and digestive tract diseases from the same hospitals. Intakes of nutrients and food groups were assessed by a semiquantitative food frequency questionnaire and analyzed by the logistic regression model adjusted for possible confounding variables. Significant trends of decreasing risk of colorectal cancer emerged with more frequent intakes of vitamin A (odds ratio [OR] = 0.32, 95% confidence interval [CI] = 0.15-0.65 for the highest tertile), β-carotene (OR = 0.25, 95% CI = 0.12-0.52), and vitamin C (OR = 0.29, 95% CI = 0.14-0.61). The protective associations were also observed for calcium (OR = 0.43, 95% CI = 0.21-0.86) and fiber (OR = 0.51, 95% CI = 0.25-1.05). Energy consumption was associated with an increased risk in the highest tertile of consumption (OR = 2.04, 95% CI = 1.01-4.12). The highest tertiles of rice, cake, and fish intakes were related to higher colorectal cancer risk (OR = 3.12, 95% CI = 1.41-6.91; OR = 2.39, 95% CI = 1.13-5.03; OR = 2.52, 95% CI = 1.21-5.26, respectively). Inverse associations of risk were found for milk (OR = 0.29, 95% CI = 0.15-0.58), kimchi (OR = 0.41, 95% CI = 0.20-0.84), vegetable (OR = 0.34, 95% CI = 0.16-0.71), and fruit (OR = 0.49, 95% CI = 0.24-1.02) intakes. This study further supports the protective effects of antioxidant vitamins and calcium associated with vegetable and milk consumptions and confirms a relevant role of dietary intake against colorectal cancer risk for Koreans.